1. The Field of the Invention
The present invention pertains to insert rod guides used with beam pumping wells and, more particularly, to rod guides used with beam pumping wells in which a reciprocating sucker rod operates a downhole pump.
2. The Prior Art
The insert rod guide of the present invention replaces the standard rod guide in those pumping applications where the fluid produced from the well contains abrasives or where the well is characterized by a crooked well bore or where the well is a horizontal well
The standard prior art insert rod guide used in beam pumping wells is typically made of a single piece of metal machined with standard tooling. The rod, which actually moves up and down as it passes through a standard rod guide, is generally made from a metal which has about the same hardness as a stationery rod guide.
When fluid produced by a reciprocating downhole pump contains abrasive material, such as sand or dirt, these abrasives accelerate rod wear within the rod guide and can actually cut through the rod guide and render it unusable. When the insert rod guide is in constant contact with the reciprocating valve rod, rod wear from the rod guide typically occurs over the entire length of the sucker rod stroke. Accordingly, if the insert rod guide is not properly monitored for wear, the reciprocating sucker rod can actually cut through the rod guide. Without a proper insert rod guide, the rod will cut into the barrel of the pump resulting in the requirement for replacement of both the insert rod guide and the pump barrel. This is an extremely expensive repair. Additionally, if the downhole pump is used in gassy wells, or it is used in a well characterized by the production of a lot of trash, operators will xe2x80x9ctagxe2x80x9d the pump, this is lowering the sucker rod string until the valve rod bushing hits the rod guide on each down stroke. The female clutch on the rod guide may be ruined and replacement of the rod guide will be necessary, even if the rod guide is not otherwise worm. With the present insert rod guide, only the female clutch (retainer collar) will need to be replaced.
For a description of reciprocating pumps of the type used for producing fluids from subsurface wells, reference is made to my U.S. Pat. No. 6,368,084, the disclosure of which is incorporated herein by reference.
The subject insert rod guide has an elongated cylindrical member with an externally threaded first or upper end of a first diameter and an internally threaded lower or second end of a larger diameter and a profiled axial bore extending between the ends. Intermediate the ends of the member is an outwardly directed, external, truncated conical shoulder. A plurality of regularly spaced bores angled outwardly from the axial bore through the shoulder. An annular sand shield is mounted on the member for axial movement therealong. The sand shield has one face tapered to mate with the shoulder. An annular hardened insert is mounted on the upper end of the member and is held in place by retainer collar. The sand shield covers the plurality of angled bores when fluid is not being pumped.